Fiber optic connector module

ABSTRACT

A fiber optic connector module includes a ferrule terminated to at least one optical fiber. The ferrule has a rearwardly facing abutment surface. The ferrule is mounted within a housing which includes a forwardly facing abutment surface for engaging the rearwardly facing abutment surface on the ferrule. The forwardly facing abutment surface on the housing is convexly rounded so that the ferrule can tilt relative to the housing.

FIELD OF THE INVENTION

This invention generally relates to the art of fiber optic transmissionand, particularly, to a fiber optic connector module.

BACKGROUND OF THE INVENTION

Fiber optic connectors of a wide variety of designs have been employedto terminate optical fiber cables and to facilitate connection of thecables to other cables or other optical fiber transmission devices. Atypical fiber optic connector includes a ferrule which mounts andcenters an optical fiber or fibers within the connector. The ferrule maybe fabricated of such material as ceramic. A ferrule holder or otherhousing component of the connector embraces the ferrule and may befabricated of such material as molded plastic. A spring may be disposedwithin the housing or ferrule holder such that the ferrule is yieldablybiased forwardly for engaging another fiber-mounting ferrule of a matingconnector device.

A pair of fiber optic connectors or a connector and another opticalfiber transmission device often are mated in an adapter which centersthe fibers to provide low insertion losses. The adapter couples theconnectors together so that their encapsulated fibers connectorend-to-end. The adapter may be an in-line component, or the adapter canbe designed for mounting in an opening in a panel, backplane, circuitboard or the like.

Various problems continue to be encountered in designing fiber opticconnector assemblies or other connector assemblies, includingapplications involving backplanes, motherboards, daughterboards and thelike. U.S. Pat. No. 6,361,218, dated Mar. 26, 2002, which is assigned tothe assignee of the present invention and which is incorporated hereinby reference, shows a fiber optic connector module which is a verysimple design and solves some of the problems of the prior art. However,problems still exist in aligning the ferrules of mating fiber opticconnectors in adapters or other fiber optic connector devices.Specifically, if a fiber optic connector module is tilted or skewedwithin its fiber optic connector, even to a small extent, the ferrulewhich is fixed within the module will tilt or skew therewith. Therefore,the flat mating face at the front end of the ferrule will be at an angleto the flat mating face of the ferrule of the mating connector, andtransmission losses may occur. The present invention is directed tosolving these problems by allowing the ferrule to tilt relative to themodule housing and, thereby, maintain a flush front face abutment of theferrule with the ferrule of the mating connector.

SUMMARY OF THE INVENTION

An object, therefore, of the invention is to provide a new and improvedfiber optic connector module of the character described.

In the exemplary embodiment of the invention, the fiber optic connectormodule includes a ferrule terminated to at least one optical fiber. Theferrule includes a forwardly facing latch surface and a rearwardlyfacing abutment surface. The ferrule is mounted in a manuallymanipulatable housing which includes a front portion encapsulating theferrule and a rear portion extending rearwardly of the front portion formanual grasping by an operator. The front portion has an open front endthrough which the mating end of the ferrule projects, and an open rearend through which the optical fiber extends. Latch means are provided onthe front portion of the housing engageable with the forwardly facinglatch surface on the ferrule for holding the ferrule encapsulated in thehousing. A forwardly facing abutment surface engages the rearwardlyfacing abutment surface on the ferrule. The forwardly facing abutmentsurface on the housing is convexly rounded so that the ferrule can tiltrelative to the housing.

According to one aspect of the invention, the ferrule includes anoutwardly projecting peripheral flange, and the forwardly facing latchsurface is defined by a front edge of the flange. The latch means isprovided by a pair of latch arms engageable with the front edge atopposite sides of the ferrule. The rearwardly facing abutment surface isdefined by a rear edge of the flange. In the preferred embodiment, apair of the convexly rounded, forwardly facing abutment surfaces areprovided at opposite sides of the housing engageable with the rear edgeof the peripheral flange.

Other features of the invention include the convexly rounded abutmentsurface being provided on a flexible arm past which the ferrule isinserted into the housing through the open rear end thereof. Inaddition, the housing defines a front-to-rear axis extending between thefront and rear portions thereof. The rearwardly facing abutment surfaceon the ferrule is a generally flat surface extending transversely of theaxis.

Other objects, features and advantages of the invention will be apparentfrom the following detailed description taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of this invention which are believed to be novel are setforth with particularity in the appended claims. The invention, togetherwith its objects and the advantages thereof, may be best understood byreference to the following description taken in conjunction with theaccompanying drawings, in which like reference numerals identify likeelements in the figures and in which:

FIG. 1 is a perspective view of a mating connector assembly, with atleast one of the connectors embodying the fiber optic connector modulesof the invention;

FIG. 2 is a perspective view of the mating connector assembly in FIG. 1,in mated condition;

FIG. 3 is a perspective view of one of the fiber optic connector modulesof the backplane connector assembly;

FIG. 4 is a perspective view of the housing of the connector module ofFIG. 3;

FIG. 5 is a perspective view showing the assembly procedure of themodule of FIG. 3;

FIG. 6 is a side elevational view of the connector module in assembledcondition;

FIG. 7 is a view similar to that of FIG. 6, showing the ferrule tiltedin one direction relative to the module housing; and

FIG. 8 is a view similar to that of FIG. 7, with the ferrule tilted inthe opposite direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in greater detail, and first to FIGS. 1 and 2,the invention is embodied in a mating connector assembly, generallydesignated 10, which includes a backplane connector assembly, generallydesignated 12, mateable with a daughterboard connector assembly,generally designated 14. The backplane connector assembly is mounted inan aperture 16 in a substrate, panel or backplane which, in theillustrated embodiment, is a printed circuit board. Specifically,backplane 18 can be considered the “motherboard” herein. Thedaughterboard connector assembly is mounted on a top surface of a secondprinted circuit board 20 which is considered the “daughterboard” herein.

Backplane connector assembly 12 includes an adapter, generallydesignated 22, which is mounted in aperture 16 in motherboard 18. Fourfiber optic connector modules, generally designated 24, are insertedinto adapter 22, through aperture 16, from the front of backplane 18.Each fiber optic connector is terminated to a multi-fiber cable 26. Eachcable is a flat or “ribbon” cable having a plurality of optical fibers.The invention herein is incorporated in connector modules 24, as will bedescribed in detail hereinafter.

After daughterboard connector assembly 14 is mounted on daughterboard20, four fiber optic connector modules, generally designated 28, areinserted into the back of the connector housing. Each module 28 isterminated to a flat, multi-fiber cable 30 similar to fiber optic cables26. Backplane connector assembly 12 and daughterboard connector assembly14 are mateable in the direction of arrows “A” (FIG. 1) to a matedcondition shown in FIG. 2, wherein the fibers of cables 26 and 30 arefunctionally connected. Latches 32 on opposite sides of adapter 22engage latches 34 on opposite sides of the daughterboard connectorassembly to hold the connector assemblies in mated condition as shown inFIG. 2.

FIG. 3 shows one of the fiber optic connector modules 24 which areinserted into adapter 22 as described above. Specifically, each module24 includes a ferrule 36 terminated to one of the multi-fiber cables 26with ends 26 a of the fibers exposed at a mating face 36 a of theferrule. The ferrule includes a pair of alignment holes 36 b opening atmating face 36 a. The ferrule is captured by a manually manipulatablehousing, generally designated 48 (FIG. 4), which includes a frontportion 38 a which actually captures the ferrule, and a rear portiondefined by a pair of laterally spaced arms 38 b that are graspablebetween an operator's finger. Ferrule 36 has a peripheral flange 36 c.Front portion 38 a of housing 38 includes a pair of forward latch hooks38 c on two opposite sides of the housing and a pair of flexible latcharms 38 d on the other two opposite sides of the housing. A chamferedlatch boss 38 e is formed on the outside of each laterally spaced arm 38b for latching the ferrule within adapter 22 by means of latch meanswithin the ferrule but not visible in the drawings. The manuallygraspable arms include serrations 40 on the outsides thereof tofacilitate manual grasping thereof.

FIG. 5 shows that ferrule 36 is insertable into housing 38 of connectormodule 24 in the direction of arrow “B”. The ferrule moves withinchannels 38 f inside arms 38 b and through an open rear end 38g of frontportion 38 a of the housing. The ferrule becomes latched in a positionprojecting out of an open front end 38 h (FIG. 4) of the housing and islocked in the position shown in FIG. 3 by forward latch hooks 38 c andflexible latch arms 38 b engaging opposite sides of flange 36 c of theferrule.

Specifically, housing 38 of module 24 is hollow or open-ended as definedby open front end 38 h (FIG. 4) and open rear end 38 g (FIG. 5). Thehousing, thereby, defines a front-to-rear axis 44 through the center ofthe housing. When ferrule 36 is assembled in the housing, flange 36 c ofthe ferrule defines a forwardly facing edge 46 which forms a forwardlyfacing latch surface for engagement by forward latch hooks 38 c of thehousing. The flange has a rear edge 48 which forms a rearwardly facingabutment surface engageable by the fronts ends of flexible latch arms 38d of the housing. Peripheral latch surface 46 and peripheral abutmentsurface 48 extend generally transversely of axis 44.

The invention contemplates that housing 38, and particularly the frontends of flexible latch arms 38 d, be provided with a unique forwardlyfacing abutment surface 50 for engaging the rearwardly facing abutmentsurface 48 on the ferrule. Specifically, referring to FIG. 6 inconjunction with FIGS. 3-5, it can be seen that forwardly facingabutment surface 50 is convexly rounded as it faces the straight ortransverse abutment surface 48 of ferrule 36. This allows the ferrule totilt relative to housing 38 in the event that the housing somehow isangled or skewed when presenting front mating face 36 a of the ferruleto the front mating face of a ferrule of a complementary matingconnector.

The tilting movement of ferrule 36 relative to housing 38 is shown inFIGS. 7 and 8. In FIG. 7, it can be seen that the ferrule has tilted orrotated about convex surface 50 in the direction of arrow “C”. In FIG.8, ferrule 36 has been tiled in the opposite direction relative tohousing 38 in the direction of arrow “D”. These depictions of FIGS. 7and 8 clearly show how the ferrule can tilt or rock back and forth asits abutment surface 48 rolls back and forth over convexly roundedabutment surface 50 at the front ends of flexible latch arms 38 d. Inother words, there is a sort of tilting floating movement of the ferrulerelative to the housing to accommodate misalignments when the connectormodule is mated with a complementary mating connecting device.

Finally, while the invention has been shown and described herein inrelation to fiber optic connector modules 24 used in adapter 22 (FIGS. 1and 2) of backplane connector assembly 26 of mating connector assembly10, the connector modules can be used in a wide variety of applicationsother than the assembly shown in FIGS. 1 and 2.

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or centralcharacteristics thereof. The present examples and embodiments,therefore, are to be considered in all respects as illustrative and notrestrictive, and the invention is not to be limited to the details givenherein.

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 11. A fiber optic connector module, comprising: aferrule terminated to at least one optical fiber, the ferrule includinga rearwardly facing abutment surface; and a housing including a frontportion from which the ferrule extends, the housing including aforwardly facing abutment surface for engaging the rearwardly facingabutment surface on the ferrule, the forwardly facing abutment surfaceon the housing being convexly rounded so that the ferrule can tiltrelative to the housing.
 12. The fiber optic connector module of claim11 wherein said housing defines a front-to-rear axis, and saidrearwardly facing abutment surface on the ferrule is a generally flatsurface extending transversely of the axis.
 13. The fiber opticconnector module of claim 11 wherein said ferrule includes an outwardlyprojecting peripheral flange, and said rearwardly facing abutmentsurface is defined by a rear edge of the flange.
 14. The fiber opticconnector module of claim 13, including a pair of said forwardly facingabutment surfaces at opposite sides of the housing engageable with therear edge of said peripheral flange.
 15. The fiber optic connectormodule of claim 11 wherein said convexly rounded abutment surface is ona flexible arm past which the ferrule is inserted into the housingthrough an open rear end thereof.